微网黑启动恢复的关键控制技术及优化决策系统研究

Microgrids black start and service restoration is an efficient pattern to realize the self-healing function of smart distribution grid, but magnetizing inrush current suppression, unbalanced load restoration, stability and other key issues have a direct impact on the successful implementation of service restoration. The project begins with the basic control technologies and methods of inverter interfaced distributed generation (IIDG) and establishes a nonlinear dynamic model based on IIDG and the transformer energized circuit to investigate the interaction mechanism between them. Afterward, an impulsive flux control strategy of IIDG is designed to restrain magnetizing inrush current. According to the unbalanced condition at early stage of the microgrids black start, the transfer coefficients of unbalanced voltage factor in islanded mode and the compensation capability for unbalanced voltage of IIDG are studied. Then an optimal restoration model for the unbalanced loads is presented, and the individual phase control of IIDG is designed to achieve the active synchronization between unbalanced islanded microgrids by the construction of adaptive synchronous closing model. Furthermore, the modal perturbation method is applied to analyze the dominant eigenvalue and its contribution rate for late stage of microgrids service restoration and to construct the small signal stability index for islanded microgrids. Subsequently in adopting fuzzy reasoning, an on-line scheduling strategy of droop coefficients is proposed by the study of relevance between the droop coefficients and the stability index. And with the consideration of the stability constraint the optimal model for late stage load restoration is established. On this basis, an optimization and decision system for microgrids black start and service restoration is presented. Generally, the implementation of this project will provide the theoretical foundation and the technical support for microgrids black start and service restoration.

微网黑启动恢复是智能配电网自愈功能的一种有效实现方式，但励磁涌流抑制、不平衡负荷恢复及稳定性等关键问题直接影响其恢复过程。本项目从微网黑启动恢复中逆变型分布式电源（IIDG）的控制技术和手段入手，结合IIDG和变压器励磁电路建立非线性动力学模型，探讨交互作用机理，进而设计IIDG的脉冲磁链控制策略，以抑制励磁涌流；针对黑启动前期的不平衡条件，研究孤岛微网中电压不平衡度的传递系数，据此探寻IIDG电压补偿能力约束，建立不平衡负荷恢复优化模型，设计不平衡子微网间自适应同期合闸模型和分相控制策略；应用模态摄动法研究后期负荷恢复时微网主导特征根及贡献率，建立小干扰稳定指标，探索下垂系数与稳定指标的关联性，设计基于模糊推理的下垂系数调整策略，并计及稳定约束建立黑启动后期负荷恢复优化模型。在此基础上，全面构建微网黑启动恢复的优化决策系统。本项目的实施为微网黑启动恢复提供理论依据和技术支撑。

微网黑启动恢复是保障敏感负荷可靠供电和安全运行的关键技术，可为其自愈和自治功能提供理论和应用支撑。本项目研究了逆变型分布式电源（IIDG）和变压器励磁电路建立非线性动力学模型，设计了IIDG的脉冲磁链控制策略以抑制励磁涌流；研究了孤岛微网中电压不平衡度的传递系数，建立不平衡负荷恢复优化模型，设计了不平衡子微网间自适应同期合闸模型及策略；研究了基于模糊推理的下垂系数调整策略，计及稳定约束建立了黑启动后期负荷恢复优化模型。项目提出了基于时变脉冲的IIDG磁链控制方法，从非线性动力学角度揭示IIDG和励磁涌流的交互机理，既满足电压约束又使磁链轨迹快速脱离饱和。提出了黑启动前期不平衡微网的主动同期控制策略，满足了多个接入点的分相自适应同期要求；建立了计及不平衡电压约束的微网黑启动不平衡负荷恢复优化模型，实现多个电源的不平衡负荷分担。分析了慢动态电源延时、IIDG下垂系数对孤岛微网小信号稳定的影响，提出了一种基于时滞模型预测控制算法的稳定增强控制策略，实现微网黑启动过程IIDG下垂系数的在线调整，保证了黑启动后期负荷恢复的稳定性要求。本项目成果将大幅改善微网黑启动和故障恢复的执行效果，为微网的组网设计和紧急控制发挥重要作用，为微网技术的发展提供有参考借鉴意义和应用价值的研究成果，其关键技术和方法也可进一步应用到新能源接入的主动配电系统。